


Violet Sky

by RegisteredNonsense



Category: Fire Emblem Series, Fire Emblem: Fuukasetsugetsu | Fire Emblem: Three Houses
Genre: BENCHED UNTIL I FINISH CF AND SN IM SORRY, Flayn Dies, and spoilers for all routes, but expect to ache, spoilers for major church related topics, tags will be edited as i go, this is gonna be a ride buckle up
Language: English
Status: In-Progress
Published: 2020-05-22
Updated: 2020-08-02
Packaged: 2021-03-03 03:54:06
Rating: Mature
Warnings: Graphic Depictions Of Violence, Major Character Death
Chapters: 3
Words: 4,444
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/24318382
Author URL: https://archiveofourown.org/users/RegisteredNonsense/pseuds/RegisteredNonsense
Summary: How different would the timeline be if Seteth had come to help vanquish the Death Knight upon Flayn's capture? How far can one old saint descend into madness upon her death?
Kudos: 9





	1. Paraloge: A Tragic Catalyst

An accident. One of his greatest nightmares had finally come to pass with Flayn as her disappearance was quickly noticed. While he initially denied the thought that Flayn was now out of his reach and far enough that his senses could not find her, the parental instinct to track her down kicked in just as fast. His daughter, his only remaining family that had not yet gone dormant or transformed into their more draconic state for good, had disappeared. He was desperate, disguises be damned if it came to that.

Though he resented seeking help from Rhea for matters that regarded Flayn, and though he certainly did not trust Byleth, he had no other choice. Every pair of eyes that could see, every hand that could reach, every voice that could shout would be needed to find her. Within minutes the entire monastery was in a desperate search for her. No one was allowed in or off campus for the moment, though Seteth prayed that Flayn had not been magicked away off Garreg Mach.

With instincts running wild Seteth had a very brief moment of clarity, the same kind that saved him from injury during the war all those decades ago. Follow Byleth it told him, and so he obeyed. Finding the professor and a myriad of students from various houses did not take him long. They had found the only viable lead in Flayn’s whereabouts which brought them to an out-of-the-way quarters and an injured Manuela, her hand pointing to an open stairwell. Whatever the cost Seteth would follow every lead to its end. A bitter, violent stir in his head made the worst he feared manifest in the back of his mind and he prayed once again that his saintly clarity was not foretelling death.

The worst was in front of him and all students that had joined Byleth down the stairwell and into the catacombs. The Death Knight had Flayn, among another student, and his forces stood between him and his daughter. Of course he listened to the professor’s swift tactics that were guiding the students and ultimately assisting in his movements as well. Within no time they were close to the knight in question. Seteth could feel ages of power tucked away for his humanity’s sake surge into his hands. Ages of near godly strength and indomitable will light up within him for the first time in centuries as he stares the Death Knight down, demanding Flayn’s release. Before either could make a move and get in range a flash of magic beside the Knight caught their attention. The Flame Emperor.

“Death Knight, you are no longer needed here. We have what we came for.”

They disappeared as fast as they came, a testament to their magical prowess that has left a bitter taste on everyone’s tongue since they first appeared. Though their face was obscured the Death Knight was audibly annoyed.

“How unfortunate, just as a worthy opponent enters my range. Allow me to leave you with a very permanent reminder of what will befall you and your students the next time we cross paths”

With a single swift motion the Death Knight’s scythe barely grazes the first student and impales Flayn beside them, the dark magic imbued within the blade stealing Flayn’s life within seconds. A few more moments, barely even a blink’s worth of time, and the Death Knight is gone leaving nothing but tragedy behind.

All Seteth could remember was screaming and rushing to Flayn’s motionless side. Upon realizing she was truly gone, essence and life force nonexistent, Seteth fell quiet. His wailing ceased, his voice all but gone. He had lost his daughter before his very eyes. His one and only remaining tether to the mortal world had frayed and all but snapped. Byleth and the students, after seeing to the unconscious girl that had been beside Flayn was taken out of the catacombs immediately, were uncertain what to say and do.

“Seteth…I’m sorry…” Byleth spoke softly to him.

“None of this is your fault…” he rose, Flayn’s body in his arms “I will see to her burial alone…”

Quietly he exited the catacombs. Quietly he stirred from within, a violent, ruthless, age old storm driving bloodlust and feral power to right underneath his skin. He will kill the Death Knight no matter how many must fall before them.

‘Cethleann…I will rend this land to shreds to find them…I promise you’


	2. Discarded Faith

**Summary for the Chapter:**

> Fueled by growing desire for revenge, Seteth launches his assault against the Flame Emperor in an attempt to gain information on the Death Knight, though his rage only blinds him in his charge as he turns his anger on both Byleth and the Church of Seiros.

Seteth was not seen by anyone in the monastery for months as he mourned his daughter’s death and stirred over the thoughts of killing the Death Knight. If there were any reason in the world for him to retain his human form it was the tactical advantage of having a human form to begin with. He could gather information in the night, bring the rest of his powers within reach and remind himself of what made him a Saint.

He was also a mere eye’s twitch away from discarding his humanity and transforming into his winged form to rain hellfire upon Fodlan once he remembered the proper incantation. It had been quite a long time since he has had to summon such power from within. The last time he transformed was thousands of years ago during a skirmish and several more times during the war. He put his primal form to rest after hearing Macuil renounce all of mortal life, but he has long since forgotten how to call upon it as a result. Unlike Seiros and his siblings, Seteth had other things to focus on aside from his own power. Or rather, he used to.

Now all Seteth has been thinking of is murder of the most violent and drawn out nature he can imagine. He could think of no other ending fit for the one who took his family away from him but the towering, ever present blockade remained between him and his goals. He has no intel on who the Death Knight is or where they have gone. His only clue is the Flame Emperor, and even they are shrouded in as much infuriating mystery as the Death Knight. If he can find them however, or finally capture them during a battle, he may be able to find stable footing in hunting the Death Knight down. Of course he’d have to call upon far more power than what he has allowed the students of the monastery see.

Seteth stirred within himself. Though he has not been seen by the students of the monastery he has been seen by a choice few staff members for reports and any happenings on campus. He was less than thrilled to hear Byleth had obtained the Sword of the Creator. It reminded him of every stolen soul at Zanado and the loss of his beloved in the war. Then the news that Jeralt had been murdered only prolonged his mourning period for Cethleann, and reading his diary only solidified his distrust of Rhea. His ears were braced for additional grim news ever since, and every knock on his door reverberated in his bones. What would be next that would remind him further of the ones he has lost. The second round of knocking told him he wasn’t just hearing things.

“Sir? I have news from Lady Rhea” the messenger said.

“…speak” he said through the door, not wishing for eyes to lay on him presently.

“Lady Rhea will be entering the Holy Tomb with Professor Byleth and some of their students later this month. She said she wishes for you to be present”

‘What could she be thinking…’

“Tell her I will be present. That is all…”

“Yes sir.”

Seteth returned to his chair upon hearing the courier’s footsteps fade. The request only made his head hurt but if Rhea wished to enter the tomb with Byleth then their possession of that sword was no mere happenstance.

‘Whatever she did to Byleth…the truth of it could come to light in that tomb. What makes this worse is my foresight, once clouded, is now clear. Visions of the Flame Emperor fill my head. I have to be there. I must…’

It took him days to collect himself, days that felt like mere hours one moment then week after week the next, but eventually, he had finally cleared the fog enough to return to the public eye. His mourning was far from over, however, and signs of it showed on his person. His hair had grown slightly, his eyes far more weary and tired, and his frame was slimmer than before. The circlet he wore upon his head to symbolize his faith in Rhea, in Seiros herself, had never felt so ill-fitted to his body before.

His ears, while still hidden under the layers of his now shoulder length hair, were still well enough to hear conversations far down the hall and around the corner.

“Professor, I am sure you are well aware that Seteth is still going through a very difficult time in his life, but I assure you he will be alright. Time heals all wounds with each passing moment.” Rhea spoke to Byleth.

‘You’re lying…time heals nothing. Time only prolongs the pain.’ He thought to himself.

“I ask that you be gentle with him. Though he may be present in the Holy Tomb with us and your students, he may still be deep in mourning. I know this may also still be a difficult time for you as well, but this is a process that must be carried out. You must go to the tomb Professor”

“I understand Lady Rhea, but what if he is incapable of coming? Last I heard he looked very ill”

“Flayn was his last remaining family Professor. You looked quite ill yourself when you returned after Jeralt’s murder, may the goddess bless him. These are natural feelings and ailments that while on the outside look sickly and frightening, they are in fact very healthy. If either of you two felt nothing and looked as if nothing had happened, then that is the concern. Seteth will be alright. He needs more time, but this is a critical moment for you and for your students, and I wish him to be present for it”

‘Your blessings mean nothing for those who you killed for not following you…’

“Lady Rhea, Professor, my apologies for such a late arrival…” Seteth said with a slightly broken voice.

“It is quite alright Seteth, you are not late at all. We were waiting for you to arrive, and now we may begin entry of the Holy Tomb. I do hope you are well enough Seteth, though I do not hold anything against you if you wish to return”

‘What choice do I have’

“I am well Lady Rhea. My appearance is presentable, I hope”

“Your appearance is quiet natural for someone in mourning. You need not worry of natural motions, and you appear quite clean and put together regardless. Come, we will begin”

“Yes…Archbishop”

As the group moved to enter the Goddess Tower all Seteth could keep his focus on was that of Byleth’s light mint colored hair and eyes. Their energy and their spirit all registered as Nabatean to Seteth’s senses, though he did not believe it so. Being capable of wielding Sothis’ sword, on top of their current appearance, only sounded alarm to him. Seiros truly was trying to revive Sothis through Byleth.

‘A bereaved daughter trying through means of necromancy to revive their mother. How many others has she attempted this with?’

Byleth’s anomalies after birth were not the only ones he had found records of. In fact, every couple of decades, there would be a child born in the church that would have the same condition. No heartbeat, no cry or emotion, and a mother dead upon their birth. He remembered Sitri, how she had difficulty showing even the slightest emotion unless in the cases of the rare happiness Jeralt brought her. He wonders how many more books he had burned contained more hidden records of misdeeds and ill-gotten power.

Remembering all those books he burned without question was beginning to make him sick. Sick enough that he had been distant and partially unresponsive the entire way down to the tomb. He hardly realized that, for a time, his hearing had been muffled as he sat in his thoughts, the voices of the students barely a whisper in the brain fog. Only when he heard Rhea’s voice speak to Byleth to sit upon Sothis’ throne did he finally return to the waking world, remembering his other reason for agreeing to come along. He needed to focus for his clarity told him the Flame Emperor would be here.

Words did not entirely process in his head as he watched Byleth sit upon the goddess’s throne, their new Nabatean energy striking his soul with each pulse. If Sothis were somewhere between the folds of time, something like this would not be necessary. He accepted Cethleann’s death, as painful as it may be, and he has long accepted Sothis’ departure from this world. It was painfully clear that Seiros had not.

As his focus pulled him back into the fog he watched Rhea’s expression become sullen as Byleth shook their head. As he expected Byleth did not receive a revelation nor did they remember the throne.

“What could possibly be missing? We were so close…”

“Lady Rhea what are you-“

Before Seteth could finish questioning her, his senses lit up, more visions of the Flame Emperor filled his head as Imperial soldiers stormed the tomb. In the front of the raid was the Flame Emperor themselves.

“Take all of the crest stones, kill anyone who attempts to interfere!” the Flame Emperor commands.

“Insolence! How dare you defile this sacred, holy tomb! Professor, Seteth, do not allow this heretic to leave with the crest stones!”

Without hesitation Seteth begins walking forward, throwing an arm out to tell Byleth to halt. An urge deep within his chest to claw at something rising, his eyes focused solely on the Flame Emperor.

“You…I have waited, longed even, for the day we finally crossed paths again. You are not leaving this tomb. I will not kill you, not yet, but you will not slip from my grasp again!” Seteth screamed, a slumbering power now awake within his soul as his body became engulfed in a glowing green aura.

Recognizing the power growing before her, Rhea raced forward. She couldn’t allow the students to see his form. She couldn’t allow the truth she has kept secret for so long come to light. Not here in the tomb of all places, not in front of the future lords of Fodlan.

“Seteth! Revenge is not worth the price you must pay!” she begged him.

“I do not care! I will have the Death Knight’s head and the Flame Emperor is my key! I will have revenge for Cethleann!”

As Seteth’s power rose so too did the glow around him until his person was no longer visible. Both the Imperial soldiers and the students stepped away from the glowing, near blinding light that broke way to a silver winged beast. Behind the mask, the Flame Emperor was hardly surprised.

“As expected, the Immaculate One is not the only beast controlling Fodlan. To think Seteth has been among their kind this whole time though. This will make things more difficult. Forget the crest stones! The truth revealed is enough for our cause for now!”

Glowing red eyes peered down at the Flame Emperor as Seteth ignored the plea from Rhea behind him.

“You think you get to just walk out of here?! I care not for your soldiers! Go ahead and let them run! But you, YOU will be going nowhere!”

“Seteth no! There is no need for this violence!” Rhea continued to plead.

Rather than wait for a spell to form at his lips, Seteth instead charges the Flame Emperor with sharp claws. The sheer force knocked the Flame Emperor back and swiped the mask clean off. Violet eyes now stare up at red ones. Strands of white hair fall out from under the helmet. The tomb fell silent, then Seteth’s anger mounted.

“Edelgard…foolish child! How many more will I be betrayed by?! At least this saves me the trouble of hunting your identity down!”

“Hunt me all you wish, the Church will pay for its crimes against humanity! You will no longer hold Fodlan captive for your selfish gains! Hubert! We must leave!”

“You do not get to run!”

Another swipe that missed as Hubert warps Edelgard out of the tomb, the crest of Cichol appearing clear over Seteth’s forehead for a brief moment. Scattered stones and broken bricks dance at his claws as he lets out a piercing roar, a beam of magic firing from his mouth towards the sky carving a path through the ceiling.

“You cannot run from me! Even he cannot warp you out of my reach!” Seteth roared.

“Seteth I beg of you, enough! Hunting her will not bring your daughter back!”

“This is not about revival! This is revenge!” Seteth roared, flying through the path he carved to the surface.

Through the commotion the Imperial soldiers fled the tomb, some of the students trying to race after them. Beside the broken wall Claude desperately tries to help Dedue and Felix calm Dimitri, who was slowly descending into madness.

“Lady Rhea, what do we do?” Byleth asks, watching the scene before them.

“Professor…we cannot allow Seteth to rampage. Please, I beg of you professor. I can handle the students. I will answer their questions. Please, stop Seteth.”

Racing towards the exit of the tomb Byleth could hear the manic screams from Dimitri below and the piercing roars of Seteth above. He had taken to the skies, circling a portion of the field before them. Even with the length of the Sword of the Creator at their disposal Seteth was far too high for them to reach and too fast for any archer to shoot down. Out the corner of their eye was the glow of dark magic. Byleth turned their head to see Hubert and Edelgard.

“This was not exactly the way we planned this, but at the very least we have this chance. Professor, you’ve seen the truth now. The truth of the Church of Seiros. I will give you this chance professor. Join us in this fight! We will-“

“Lady Edelgard! Get down!”

Before Edelgard could continue Hubert pulled her away as Seteth dove down and breathed more magic at the trio as he landed. Byleth rolled close to the edge of the cliffside, their sword still in hand. His roar shook the earth.

‘He’s beyond reason already…even I might not be able to reach through to him with words alone’ Byleth thought as they rose to their feet, rushing to stand between Seteth and Edelgard.

“You…you would protect them?! I trusted you! I put my faith into you and even YOU have betrayed me!”

“You’ve gone mad Seteth! I’m only here to make sure you don’t kill them!” Byleth yells at them.

“I don’t want them dead, not yet. I want answers! The one known as the Death Knight is my goal! So answer me foolish child! Where is that knight?! Where is the one that took my daughter from me!!!” he roared, leaning in to stare Edelgard down.

“I do not know his whereabouts Seteth! He is not mine to command!”

“LIES!!! I saw you! I saw you there with him! If you won’t answer me, then perish where you stand! All three of you!”

Seteth pulled back to prepare another beam, taking to the skies to leave both Byleth’s and Hubert’s range. Just before he could fire upon them another silver beast charged into Seteth, knocking him out of the air, the beam missing the trio below by a few feet as it shattered the earth and destabilized the cliffside. The two winged beasts now stand against each other.

“Seiros?! What are you doing?!”

“This ends now Seteth! Enough! Revenge is never worth the price! I will not just stand by and watch you use our people’s power for such wickedness!” the other beast roared at him.

“Enough with your so-called wisdom! I’ve spent too long in ignorance! Too long have I burnt books and spilled blood all for you! I should have never come to you with her! I should have never fled the isolation of the mountains! I should have never returned had I known what your true goal of Garreg Mach was!”

Beside the two winged creatures, Hubert helped Edelgard to her feet.

“Lady Edelgard, this situation is too much for just us. We must flee!”

“Not without the professor! Surely they survived that last attack!”

“We have no time!”

Once again Seteth took to the skies, the wind pressure stirred from his wings alerting the pair below him. The other beast took to the skies just as fast trying to stay between him and the people below.

“Get out of my way!”

“I will not! Too much damage has been done! I will not allow you to needlessly kill them!”

“How rich coming from you. You who sentenced those expressing free will to death. I know I am guilty of supporting you, guilty of standing beside you and saying nothing as you enforced your law upon the humans of this world, but I know those humans did not have to die. They died for nothing! Now enough talk! If I must destroy even you to find that damn knight, I shall!”

“It’s not worth it Cichol!”

“Do not speak my name Seiros!”

Another roar and Cichol sends a barrage of magic towards Seiros, the scattered shots landing beside Edelgard and Hubert while a stray knocks Byleth back. The already shattered earth gives way, sending Byleth into the gorge below. Only a single scream indicated that something had happened to them.

Realizing his hunt had left, Cichol flies off leaving Seiros, and Garreg Mach, behind him.


	3. Part Two: Violet Sky

**Notes for the Chapter:**

> This chapter is best read in Jeralt's voice.

In the days following Seteth’s attack Rhea struggled to maintain control of both Garreg Mach and the church’s influence in Fodlan. While Rhea was able to assure there were no witnesses for her transformation, Byleth, houses of students, and the house leaders themselves witnessed Seteth’s own and all he spoke in the tomb. The Archbishop was unable to silence those who had heard the truth. All she could do now was rally those who were not present at the Holy Tomb and fortify Garreg Mach, fearing a potential rebellion.

A majority of the students who were present returned home at once out of fear or an interest in spreading the tale of what they saw to more powerful lords.

Claude von Riegan slipped away to the Alliance before the rest of the Golden Deer could follow, several plans to unify Fodlan now far out of line. The lords of the region were split between believing the students that had returned and waving off what they thought were lies, not wanting conflict with the Church of Seiros. While the other lords were fighting, Claude set his sights to the skies. Knowing he’s a witness to something he should have never seen, Claude steels himself for possibility of Seteth coming for him while he keeps the Alliance under control.

Edelgard von Hresvelg returned to the Empire to consider her options in waging war with the Church of Seiros. While war was initially planned after the assault in the Holy Tomb, Seteth’s betrayal of the church and his declaration to hunt the Death Knight have changed her direction. Upon hearing word that the Archbishop has fortified Garreg Mach and rallied the Knights of Seiros from their missions, it was decided that protection of Enbarr takes priority. Within days rumors of a shining silver beast in the sky just off the coast spread throughout not only the Empire but within the entirety of Fodlan. The Empire would be quiet for the next few years as Edelgard watched the skies and wondered where Seteth, and their beloved professor, could have gone.

The Holy Kingdom of Faerghus found itself in a worse spot than the other regions. Many of the lords of the Kingdom did not believe the students that witnessed Seteth’s transformation and several other students remained silent. The Church’s beliefs and influence still had a considerable hold on Faerghus and its people. Its prince, however, was in a much worse state. Upon learning that Edelgard had been the Flame Emperor the entire time, Dimitri Alexandre Blaiddyd spiraled into madness. All attempts to calm the prince’s madness failed as Dimitri continued to allow his blind thirst for revenge to consume him. Within months Dimitri went missing, and the Holy Kingdom was left to the lords.

For five long years Fodlan remained in a quiet but tense era. All regions kept to themselves save for merchants going back and forth between the three nations. Garreg Mach fell eerily quiet, shutting down the school portion of the monastery to repair the damages done by Seteth’s outburst in the Holy Tomb.

The Alliance and the Empire both kept their focus on maintaining control within their borders and establishing a force to deal with the possibility of facing Seteth, and the Knights of Seiros, as more and more sightings of a silver beast in the sky came through over the years.

The Holy Kingdom never ceased their search for their missing Prince, but as the years went by the efforts slowly waned as more focus was spent on strengthening ties with the Church of Seiros and maintaining neutrality with the other two nations. The search by the Kingdom halted entirely, however, after a report that a giant tower had risen from the sea off the Rhodos Coast days before the Millennium Festival. The silver beast was spotted once more flying towards the tower then disappearing towards the top. Only Dedue, who had remained ever vigilant in his search for Dimitri, dared to venture out towards the coast after the rise of the tower. Seteth wanted the Flame Emperor with the same ferocity as Dimitri, and that alone made Dedue wonder if Dimitri would dare seek alliance with Seteth to breach the Empire for revenge.

In the tower that had risen from the earth through what appeared to be magic alone, a sinister power has emerged from the shadows in Fodlan while Byleth, after remaining in fate’s arms for five long years, has awakened just downstream of a fortified and drastically different Garreg Mach.

**Notes for the Chapter:**

> Me? Finishing a chapter before 12am?

**Author's Note:**

> OOPS it's Fell Seteth time! In which I commit the ultimate sin of killing Flayn to set Seteth off into insanity. Goddess have mercy on me. Tbh I can't believe I have to click Major Character Death right off the bat.


End file.
